The load rating of rolling bearings, inter alia, also depends to a considerable extent on the number of rolling elements. Full-type rolling bearings contain the largest possible number of rolling elements and therefore provide a theoretical optimum load rating. A disadvantage of full-type rolling bearings is the higher friction. On account of this greater dissipation loss in the bearing, the speed limit of the bearings drops to about half the value of cylindrical roller bearings with retainers.
In order to eliminate these disadvantages, it has been conventional practice for a long time to dispense with a maximum number of rolling elements and to use the space thus obtained, compared with a full-type design, for a retainer. Thus, although it is possible for conventional cylindrical rollers with retainers to be operated at higher speeds, a reduced number of cylindrical rollers and thus a reduction in the load rating must be tolerated on account of the space required for the retainer.
Such a rolling bearing has been previously disclosed by DE 931 684. Its cylindrical rollers are accommodated in a sheet-metal retainer of the generic type, the webs of which are provided with projections which are twisted in a radial direction, so that adjacent rolling elements in the region of the pitch circle are separated from one another by the sheet thickness. However, this sheet-metal retainer is made of a thin material, so that it cannot be used at all in a bearing which is subjected to very high loads. Another disadvantage consists in the fact that there is a relatively large distance between two adjacent rolling elements in the circumferential direction. This distance is composed of the actual web width and the bent-over projections. There is also the fact that the bending radii of the bent-over projections additionally increase this web width even further.
Another retainer of the generic type having twisted webs has be previously disclosed by DE 36 03 413 A1. This retainer is likewise produced from sheet metal and has webs which extend with their axial ends into the side rings over part of the width of the latter and are radially oriented by being rotated by 90° about their axes. In addition, the webs have holding lobes which are bent alternately into the one or the other adjacent pocket. In this case, these holding lobes are defined by radial notches which are already provided in the flat state of the retainer strip. This retainer, too, has the disadvantage of very low stability.